Today's on-board maintenance systems are so advanced and comprehensive it's almost like having a maintenance tech riding along with you

By Paul Abelson
senior technical editor

Remember the old Suburban Auto Group commercials with the “trunk monkey”? The one where the car driver could hit a button on the dash and a monkey appeared, performing whatever task the driver wanted done.

Wouldn’t it be nice to have a handy little button on the dash that once you pushed it, a mechanic just showed up magically and took care of routine maintenance while you’re going down the road?

It’s not as far-fetched as it may seem. There are many on-board maintenance systems that do just that – but without the mechanic, or monkey, riding shotgun.

To extend preventive maintenance intervals, many operators extend oil drains using bypass filters, but still have to bring their trucks in for a “dry” PM, which does not include an oil change, in order to get the chassis lubed.

Truck makers try to require all PM tasks to be performed at the same mileage, but extending one task such as oil drain, while saving the cost of oil and filters, does not mean you do not need to come off the road for other preventive maintenance needs.

On-board automated chassis lubrication systems allow you to stay on the road.

Automatic greasers consist of a central reservoir, a pressure pump, a manifold to accumulate and distribute grease to hoses and special fittings that replace traditional Zerk fittings at grease points. The advantages of using automatic greasing are:

Grease is distributed completely. No fittings are missed because of human error.

Greasing is virtually continuous so you can adjust maintenance intervals according to oil analysis results.

Material costs for greases can be 25 percent less because of more accurate dispensing, reducing waste.

Just make sure the reservoir doesn’t run out of grease.

Just as engines suffer bearing damage and risk seizing up if oil is contaminated or if a sufficient quantity is not available, bearing, suspension, steering and driveline damage results from inadequate or contaminated grease.

In one component study, lubrication-related failures account for more than half of chassis failures – 34.4 percent from inadequate lubrication and
19.6 percent from contamination.

Systems can be ordered on trucks, purchased through dealer networks for dealer installation, or put on by your favorite independent shop. Unless you are skilled at truck maintenance, I’d advise against doing it yourself since chassis lubrication is critical to truck longevity and reliability.

If weight or costs are critical, an alternative is a centralized lubrication system with a central block manifold, hoses and fittings leading to as many as 12 points per block. You grease one point, and grease will go to every fitting. You control how much.

Because you can retrofit it, you can wait to install it and save the 12 percent excise tax on new truck equipment. For the first six months, you might want to have new truck service done at a dealer, in case there are warranty issues with the truck.

Tires account for a significant share of maintenance and operational costs, second only to fuel. Properly maintained, a
$400 to $500 tire can give well over 150,000 miles in its first life, and three to as many as five subsequent lives at half that price when properly retreaded.

Far too many tires never even make it through their first life. Some are seen along the roadside, as thrown treads, others as casings in the scrap heap when careful inspection identifies them as having internal damage and not retreadable.

The main reason is low air pressure. At the Tire Symposium held at the Great American Trucking Show, Harvey Brodsky, managing director of the Tire Repair and Retread Information Bureau, paraphrased the old real estate adage about location, saying that the three secrets to long tire life “are inflation, inflation and inflation.”

Tires flex. When underinflated, they flex excessively, causing heat build-up in casings. That breaks tire cords and destroys the adhesion of tire components. A tire underinflated 20 percent or more can throw a tread or suffer damage that is identified through modern non-destructive testing.

So why doesn’t everyone check tire pressures daily? It takes time and requires effort. So we “thump” tires to make sure they have air. But that’s all thumping tells you. In test after test conducted at truck shows, drivers have been unable to differentiate pressures above 65 psi by thumping. Remember, 20 percent underinflation destroys tires. That’s 75 to 80 psi, undetectable by thumping.

The next on-board systems, tire pressure monitoring (TPMS) use sensors for each tire. The sensors strapped on the rim or in the valve assembly measure and transmit psi to receivers. They can be hand-held for use during pre-trip inspections or they can be dash-mounted. Some read pressure when activated. Others are always on and alert the driver.

Valor’s tire pressure monitor system directly measures the tire pressure and temperature, sending the data to both the driver and even to the company HQ. The system will send a warning signal when there is significant air pressure loss, a continuous slow drop in pressure, or when the temperature rises unusually.

Tire Stamp makes Tire Vigil TPMS. It can alert both drivers and fleet headquarters so arrangements can be made for any needed service. Linked to GPS, the system can search to find the closest service provider. Tire Vigil works with a variety of on- or in-tire sensors and installs without wires (except for power), usually in one hour or less. Pressure Pro, Stemco’s BAT RF and Bendix’s SmarTire all monitor signals from proprietary sensors.

Automatic tire inflation systems are even more effective in maintaining pressure. They use the truck’s air system to keep pressure at pre-set levels without driver intervention. Automatic information systems operate with fittings on wheel ends that take air through the axle and deliver it through the hub to a sealed rotary union that connects through hoses to tire valves.

When a tire is down, inflation systems direct air to that tire. Most can keep a tire full even with a puncture in it. Airgo and Pressure Guard use hoses embedded in the axle tube to carry air to the hub, while the Meritor Tire Inflation System by P.S.I. pressurizes the hollow axle. So far, it has been impractical to install inflation systems on drive or steer axles since neither use hollow tube axles.

The Spicer Central Tire Inflation System from Roadranger provides both inflation and deflation of all tires, including steer and drive axles. Air pressure can be adjusted for low speed traction on snow, sand and mud. For many operations, CTIS has proven too costly and complex for all but military vehicles and specialized trucks operating off road and under severe conditions.

Hendrickson’s TireMaax operates like other pressure monitoring systems, but in several years of field experience, they found that overinflation can also be a problem with some inflation systems. At the Great American Trucking Show, they introduced TireMaax Pro. It balances air pressure on all trailer tires continuously, to raise or lower pressure in response to changes in outside temperatures. It reduces scrubbing between dual tires, extending life.

Of course, as technology continues to advance, we will likely see more and more routine maintenance tasks taken care of by on-board systems. So, no matter how many systems are on board, routine maintenance should never be completely ignored – at least until they develop that button where a mechanic just shows up magically and does all the work while you’re grabbing a coffee and a bite to eat. LL